2009A&A...506..303Q


Query : 2009A&A...506..303Q

2009A&A...506..303Q - Astronomy and Astrophysics, volume 506, 303-319 (2009/10-4)

The CoRoT-7 planetary system: two orbiting super-earths.

QUELOZ D., BOUCHY F., MOUTOU C., HATZES A., HEBRARD G., ALONSO R., AUVERGNE M., BAGLIN A., BARBIERI M., BARGE P., BENZ W., BORDE P., DEEG H.J., DELEUIL M., DVORAK R., ERIKSON A., FERRAZ-MELLO S., FRIDLUND M., GANDOLFI D., GILLON M., GUENTHER E., GUILLOT T., JORDA L., HARTMANN M., LAMMER H., LEGER A., LLEBARIA A., LOVIS C., MAGAIN P., MAYOR M., MAZEH T., OLLIVIER M., PAETZOLD M., PEPE F., RAUER H., ROUAN D., SCHNEIDER J., SEGRANSAN D., UDRY S. and WUCHTERL G.

Abstract (from CDS):

We report on an intensive observational campaign carried out with HARPS at the 3.6m telescope at La Silla on the star CoRoT-7. Additional simultaneous photometric measurements carried out with the Euler Swiss telescope have demonstrated that the observed radial velocity variations are dominated by rotational modulation from cool spots on the stellar surface. Several approaches were used to extract the radial velocity signal of the planet(s) from the stellar activity signal. First, a simple pre-whitening procedure was employed to find and subsequently remove periodic signals from the complex frequency structure of the radial velocity data. The dominant frequency in the power spectrum was found at 23days, which corresponds to the rotation period of CoRoT-7. The 0.8535day period of CoRoT-7bplanetary candidate was detected with an amplitude of 3.3m/s. Most other frequencies, some with amplitudes larger than the CoRoT-7b signal, are most likely associated with activity. A second approach used harmonic decomposition of the rotational period and up to the first three harmonics to filter out the activity signal from radial velocity variations caused by orbiting planets. After correcting the radial velocity data for activity, two periodic signals are detected: the CoRoT-7b transit period and a second one with a period of 3.69days and an amplitude of 4m/s. This second signal was also found in the pre-whitening analysis. We attribute the second signal to a second, more remote planet CoRoT-7c. The orbital solution of both planets is compatible with circular orbits. The mass of CoRoT-7b is 4.8±0.8(M) and that of CoRoT-7c is 8.4±0.9(M), assuming both planets are on coplanar orbits. We also investigated the false positive scenario of a blend by a faint stellar binary, and this may be rejected by the stability of the bisector on a nightly scale. According to their masses both planets belong to the super-Earth planet category. The average density of CoRoT-7b is ρ=5.6±1.3g/cm3, similar to the Earth. The CoRoT-7 planetary system provides us with the first insight into the physical nature of short period super-Earth planets recently detected by radial velocity surveys. These planets may be denser than Neptune and therefore likely made of rocks like the Earth, or a mix of water ice and rocks.

Abstract Copyright:

Journal keyword(s): stars: planetary systems - techniques: radial velocities - techniques: photometric - stars: activity - stars: starspots

VizieR on-line data: <Available at CDS (J/A+A/506/303): tablea1.dat>

Simbad objects: 8

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Number of rows : 8
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 HD 41004 ** 05 59 49.6501762752 -48 14 22.888358520   9.49 8.65     K1IV 171 1
2 CoRoT-7 * 06 43 49.4690164104 -01 03 46.826642700   12.78 11.73 11.36 10.87 K0V 199 1
3 CoRoT-7c Pl 06 43 49.4690410679 -01 03 46.825797768           ~ 45 1
4 CoRoT-7b Pl 06 43 49.4690410679 -01 03 46.825797768           ~ 386 1
5 Ross 905 PM* 11 42 11.0933350978 +26 42 23.650782778   12.06 10.613 10.272 8.24 M3V 592 1
6 HD 166433 * 18 13 57.9121702992 -56 37 16.713058872   11.12 9.60     M2/3(III) 6 0
7 HD 189733 BY* 20 00 43.7129433648 +22 42 39.073143456 9.241 8.578 7.648 7.126 6.68 K2V 834 1
8 HD 219828 * 23 18 46.7341555224 +18 38 44.619358200   8.68 8.01     G0IV 105 1

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2023.01.27-22:05:54

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